U.S. Pat. No. 6,360,787 granted Mar. 26, 2002 to Robert L. Williamson relates a produce packaging machine. This type of automated produce packaging machine is used to package small produce, such as blueberries, in small plastic “clam shell” containers. This type of packaging machine generally consists of a system of conveyers that transport the containers past produce hoppers that meter produce into the containers, vibrators that level the produce within the container, and closure mechanisms that close the lid of the containers.
Heretofore, automated produce packaging systems have suffered from lost produce in the packaging process. Produce is most frequently lost during the filling process where produce metered from the hopper spills out of the containers or during the leveling process before the lids are closed in the packaging process where produce bounces out of the containers or falls between containers moving along the vibrating conveyers. Conventional packaging systems use vibrators to gently shake the conveyers, which levels the produce being piled into mounds in the containers from the hoppers. While the conveyer vibrators are useful and necessary to level the produce in the containers, they contribute to the spillage problem. Often, automated packaging systems use a single conveyer and the vibrations shake all the containers on the conveyer. Because the clam shell containers themselves are so light weight, empty containers traveling on the conveyer toward the hopper are often jarred out of alignment and jam up the packaging process. Container jams lead to lost produce. To eliminate this problem, some automated packaging systems employ separate conveyers, one for the filling station and one for a leveling station. Obviously, using multiple conveyers adds additional cost to the packaging system. In addition, the second conveyers are often run at higher speeds to move the produce through the closure process more quickly. As individual containers pass from the fill station conveyer to the faster vibration conveyers, the containers become spaced apart. With the containers spaced apart, produce again may be lost between the container as the vibrations level the produce. Ideally, a filling process and produce leveling process should use a single conveyer run, but that conveyer run should isolated from vibrations over that portion of the conveyer run where the filling process takes place.